/**
 * @file
 *
 * IPv6 layer.
 */

/*
 * Copyright (c) 2010 Inico Technologies Ltd.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Ivan Delamer <delamer@inicotech.com>
 *
 *
 * Please coordinate changes and requests with Ivan Delamer
 * <delamer@inicotech.com>
 */

#include "lwip/opt.h"

#if LWIP_IPV6  /* don't build if not configured for use in lwipopts.h */

#include "lwip/def.h"
#include "lwip/mem.h"
#include "lwip/netif.h"
#include "lwip/ip.h"
#include "lwip/ip6.h"
#include "lwip/ip6_addr.h"
#include "lwip/ip6_frag.h"
#include "lwip/icmp6.h"
#include "lwip/raw.h"
#include "lwip/udp.h"
#include "lwip/priv/tcp_priv.h"
#include "lwip/dhcp6.h"
#include "lwip/nd6.h"
#include "lwip/mld6.h"
#include "lwip/debug.h"
#include "lwip/stats.h"

#ifdef LWIP_HOOK_FILENAME
#include LWIP_HOOK_FILENAME
#endif

/**
 * Finds the appropriate network interface for a given IPv6 address. It tries to select
 * a netif following a sequence of heuristics:
 * 1) if there is only 1 netif, return it
 * 2) if the destination is a link-local address, try to match the src address to a netif.
 *    this is a tricky case because with multiple netifs, link-local addresses only have
 *    meaning within a particular subnet/link.
 * 3) tries to match the destination subnet to a configured address
 * 4) tries to find a router
 * 5) tries to match the source address to the netif
 * 6) returns the default netif, if configured
 *
 * @param src the source IPv6 address, if known
 * @param dest the destination IPv6 address for which to find the route
 * @return the netif on which to send to reach dest
 */
struct netif *
ip6_route(const ip6_addr_t *src, const ip6_addr_t *dest)
{
    struct netif *netif;
    s8_t i;

    /* If single netif configuration, fast return. */
    if ((netif_list != NULL) && (netif_list->next == NULL))
    {
        if (!netif_is_up(netif_list) || !netif_is_link_up(netif_list))
        {
            return NULL;
        }
        return netif_list;
    }

    /* Special processing for link-local addresses. */
    if (ip6_addr_islinklocal(dest))
    {
        if (ip6_addr_isany(src))
        {
            /* Use default netif, if Up. */
            if (netif_default == NULL || !netif_is_up(netif_default) ||
                    !netif_is_link_up(netif_default))
            {
                return NULL;
            }
            return netif_default;
        }

        /* Try to find the netif for the source address, checking that link is up. */
        for (netif = netif_list; netif != NULL; netif = netif->next)
        {
            if (!netif_is_up(netif) || !netif_is_link_up(netif))
            {
                continue;
            }
            for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++)
            {
                if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
                        ip6_addr_cmp(src, netif_ip6_addr(netif, i)))
                {
                    return netif;
                }
            }
        }

        /* netif not found, use default netif, if up */
        if (netif_default == NULL || !netif_is_up(netif_default) ||
                !netif_is_link_up(netif_default))
        {
            return NULL;
        }
        return netif_default;
    }

    /* we come here for non-link-local addresses */
#ifdef LWIP_HOOK_IP6_ROUTE
    netif = LWIP_HOOK_IP6_ROUTE(src, dest);
    if (netif != NULL)
    {
        return netif;
    }
#endif

    /* See if the destination subnet matches a configured address. */
    for (netif = netif_list; netif != NULL; netif = netif->next)
    {
        if (!netif_is_up(netif) || !netif_is_link_up(netif))
        {
            continue;
        }
        for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++)
        {
            if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
                    ip6_addr_netcmp(dest, netif_ip6_addr(netif, i)))
            {
                return netif;
            }
        }
    }

    /* Get the netif for a suitable router. */
    netif = nd6_find_route(dest);
    if ((netif != NULL) && netif_is_up(netif) && netif_is_link_up(netif))
    {
        return netif;
    }

    /* try with the netif that matches the source address. */
    if (!ip6_addr_isany(src))
    {
        for (netif = netif_list; netif != NULL; netif = netif->next)
        {
            if (!netif_is_up(netif) || !netif_is_link_up(netif))
            {
                continue;
            }
            for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++)
            {
                if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
                        ip6_addr_cmp(src, netif_ip6_addr(netif, i)))
                {
                    return netif;
                }
            }
        }
    }

#if LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF
    /* loopif is disabled, loopback traffic is passed through any netif */
    if (ip6_addr_isloopback(dest))
    {
        /* don't check for link on loopback traffic */
        if (netif_default != NULL && netif_is_up(netif_default))
        {
            return netif_default;
        }
        /* default netif is not up, just use any netif for loopback traffic */
        for (netif = netif_list; netif != NULL; netif = netif->next)
        {
            if (netif_is_up(netif))
            {
                return netif;
            }
        }
        return NULL;
    }
#endif /* LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF */

    /* no matching netif found, use default netif, if up */
    if ((netif_default == NULL) || !netif_is_up(netif_default) || !netif_is_link_up(netif_default))
    {
        return NULL;
    }
    return netif_default;
}

/**
 * @ingroup ip6
 * Select the best IPv6 source address for a given destination
 * IPv6 address. Loosely follows RFC 3484. "Strong host" behavior
 * is assumed.
 *
 * @param netif the netif on which to send a packet
 * @param dest the destination we are trying to reach
 * @return the most suitable source address to use, or NULL if no suitable
 *         source address is found
 */
const ip_addr_t *
ip6_select_source_address(struct netif *netif, const ip6_addr_t *dest)
{
    const ip_addr_t *src = NULL;
    u8_t i;

    /* If dest is link-local, choose a link-local source. */
    if (ip6_addr_islinklocal(dest) || ip6_addr_ismulticast_linklocal(dest) || ip6_addr_ismulticast_iflocal(dest))
    {
        for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++)
        {
            if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
                    ip6_addr_islinklocal(netif_ip6_addr(netif, i)))
            {
                return netif_ip_addr6(netif, i);
            }
        }
    }

    /* Choose a site-local with matching prefix. */
    if (ip6_addr_issitelocal(dest) || ip6_addr_ismulticast_sitelocal(dest))
    {
        for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++)
        {
            if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
                    ip6_addr_issitelocal(netif_ip6_addr(netif, i)) &&
                    ip6_addr_netcmp(dest, netif_ip6_addr(netif, i)))
            {
                return netif_ip_addr6(netif, i);
            }
        }
    }

    /* Choose a unique-local with matching prefix. */
    if (ip6_addr_isuniquelocal(dest) || ip6_addr_ismulticast_orglocal(dest))
    {
        for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++)
        {
            if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
                    ip6_addr_isuniquelocal(netif_ip6_addr(netif, i)) &&
                    ip6_addr_netcmp(dest, netif_ip6_addr(netif, i)))
            {
                return netif_ip_addr6(netif, i);
            }
        }
    }

    /* Choose a global with best matching prefix. */
    if (ip6_addr_isglobal(dest) || ip6_addr_ismulticast_global(dest))
    {
        for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++)
        {
            if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
                    ip6_addr_isglobal(netif_ip6_addr(netif, i)))
            {
                if (src == NULL)
                {
                    src = netif_ip_addr6(netif, i);
                }
                else
                {
                    /* Replace src only if we find a prefix match. */
                    /* @todo find longest matching prefix. */
                    if ((!(ip6_addr_netcmp(ip_2_ip6(src), dest))) &&
                            ip6_addr_netcmp(netif_ip6_addr(netif, i), dest))
                    {
                        src = netif_ip_addr6(netif, i);
                    }
                }
            }
        }
        if (src != NULL)
        {
            return src;
        }
    }

    /* Last resort: see if arbitrary prefix matches. */
    for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++)
    {
        if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
                ip6_addr_netcmp(dest, netif_ip6_addr(netif, i)))
        {
            return netif_ip_addr6(netif, i);
        }
    }

    return NULL;
}

#if LWIP_IPV6_FORWARD
/**
 * Forwards an IPv6 packet. It finds an appropriate route for the
 * packet, decrements the HL value of the packet, and outputs
 * the packet on the appropriate interface.
 *
 * @param p the packet to forward (p->payload points to IP header)
 * @param iphdr the IPv6 header of the input packet
 * @param inp the netif on which this packet was received
 */
static void
ip6_forward(struct pbuf *p, struct ip6_hdr *iphdr, struct netif *inp)
{
    struct netif *netif;

    /* do not forward link-local or loopback addresses */
    if (ip6_addr_islinklocal(ip6_current_dest_addr()) ||
            ip6_addr_isloopback(ip6_current_dest_addr()))
    {
        LWIP_DEBUGF(IP6_DEBUG, ("ip6_forward: not forwarding link-local address.\n"));
        IP6_STATS_INC(ip6.rterr);
        IP6_STATS_INC(ip6.drop);
        return;
    }

    /* Find network interface where to forward this IP packet to. */
    netif = ip6_route(IP6_ADDR_ANY6, ip6_current_dest_addr());
    if (netif == NULL)
    {
        LWIP_DEBUGF(IP6_DEBUG, ("ip6_forward: no route for %"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F"\n",
                                IP6_ADDR_BLOCK1(ip6_current_dest_addr()),
                                IP6_ADDR_BLOCK2(ip6_current_dest_addr()),
                                IP6_ADDR_BLOCK3(ip6_current_dest_addr()),
                                IP6_ADDR_BLOCK4(ip6_current_dest_addr()),
                                IP6_ADDR_BLOCK5(ip6_current_dest_addr()),
                                IP6_ADDR_BLOCK6(ip6_current_dest_addr()),
                                IP6_ADDR_BLOCK7(ip6_current_dest_addr()),
                                IP6_ADDR_BLOCK8(ip6_current_dest_addr())));
#if LWIP_ICMP6
        /* Don't send ICMP messages in response to ICMP messages */
        if (IP6H_NEXTH(iphdr) != IP6_NEXTH_ICMP6)
        {
            icmp6_dest_unreach(p, ICMP6_DUR_NO_ROUTE);
        }
#endif /* LWIP_ICMP6 */
        IP6_STATS_INC(ip6.rterr);
        IP6_STATS_INC(ip6.drop);
        return;
    }
    /* Do not forward packets onto the same network interface on which
     * they arrived. */
    if (netif == inp)
    {
        LWIP_DEBUGF(IP6_DEBUG, ("ip6_forward: not bouncing packets back on incoming interface.\n"));
        IP6_STATS_INC(ip6.rterr);
        IP6_STATS_INC(ip6.drop);
        return;
    }

    /* decrement HL */
    IP6H_HOPLIM_SET(iphdr, IP6H_HOPLIM(iphdr) - 1);
    /* send ICMP6 if HL == 0 */
    if (IP6H_HOPLIM(iphdr) == 0)
    {
#if LWIP_ICMP6
        /* Don't send ICMP messages in response to ICMP messages */
        if (IP6H_NEXTH(iphdr) != IP6_NEXTH_ICMP6)
        {
            icmp6_time_exceeded(p, ICMP6_TE_HL);
        }
#endif /* LWIP_ICMP6 */
        IP6_STATS_INC(ip6.drop);
        return;
    }

    if (netif->mtu && (p->tot_len > netif->mtu))
    {
#if LWIP_ICMP6
        /* Don't send ICMP messages in response to ICMP messages */
        if (IP6H_NEXTH(iphdr) != IP6_NEXTH_ICMP6)
        {
            icmp6_packet_too_big(p, netif->mtu);
        }
#endif /* LWIP_ICMP6 */
        IP6_STATS_INC(ip6.drop);
        return;
    }

    LWIP_DEBUGF(IP6_DEBUG, ("ip6_forward: forwarding packet to %"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F"\n",
                            IP6_ADDR_BLOCK1(ip6_current_dest_addr()),
                            IP6_ADDR_BLOCK2(ip6_current_dest_addr()),
                            IP6_ADDR_BLOCK3(ip6_current_dest_addr()),
                            IP6_ADDR_BLOCK4(ip6_current_dest_addr()),
                            IP6_ADDR_BLOCK5(ip6_current_dest_addr()),
                            IP6_ADDR_BLOCK6(ip6_current_dest_addr()),
                            IP6_ADDR_BLOCK7(ip6_current_dest_addr()),
                            IP6_ADDR_BLOCK8(ip6_current_dest_addr())));

    /* transmit pbuf on chosen interface */
    netif->output_ip6(netif, p, ip6_current_dest_addr());
    IP6_STATS_INC(ip6.fw);
    IP6_STATS_INC(ip6.xmit);
    return;
}
#endif /* LWIP_IPV6_FORWARD */

/**
 * This function is called by the network interface device driver when
 * an IPv6 packet is received. The function does the basic checks of the
 * IP header such as packet size being at least larger than the header
 * size etc. If the packet was not destined for us, the packet is
 * forwarded (using ip6_forward).
 *
 * Finally, the packet is sent to the upper layer protocol input function.
 *
 * @param p the received IPv6 packet (p->payload points to IPv6 header)
 * @param inp the netif on which this packet was received
 * @return ERR_OK if the packet was processed (could return ERR_* if it wasn't
 *         processed, but currently always returns ERR_OK)
 */
err_t
ip6_input(struct pbuf *p, struct netif *inp)
{
    struct ip6_hdr *ip6hdr;
    struct netif *netif;
    u8_t nexth;
    u16_t hlen; /* the current header length */
    u8_t i;
#if 0 /*IP_ACCEPT_LINK_LAYER_ADDRESSING*/
    @todo
    int check_ip_src = 1;
#endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */

    IP6_STATS_INC(ip6.recv);

    /* identify the IP header */
    ip6hdr = (struct ip6_hdr *)p->payload;
    if (IP6H_V(ip6hdr) != 6)
    {
        LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_WARNING, ("IPv6 packet dropped due to bad version number %"U32_F"\n",
                    IP6H_V(ip6hdr)));
        pbuf_free(p);
        IP6_STATS_INC(ip6.err);
        IP6_STATS_INC(ip6.drop);
        return ERR_OK;
    }

#ifdef LWIP_HOOK_IP6_INPUT
    if (LWIP_HOOK_IP6_INPUT(p, inp))
    {
        /* the packet has been eaten */
        return ERR_OK;
    }
#endif

    /* header length exceeds first pbuf length, or ip length exceeds total pbuf length? */
    if ((IP6_HLEN > p->len) || ((IP6H_PLEN(ip6hdr) + IP6_HLEN) > p->tot_len))
    {
        if (IP6_HLEN > p->len)
        {
            LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
                        ("IPv6 header (len %"U16_F") does not fit in first pbuf (len %"U16_F"), IP packet dropped.\n",
                         (u16_t)IP6_HLEN, p->len));
        }
        if ((IP6H_PLEN(ip6hdr) + IP6_HLEN) > p->tot_len)
        {
            LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
                        ("IPv6 (plen %"U16_F") is longer than pbuf (len %"U16_F"), IP packet dropped.\n",
                         (u16_t)(IP6H_PLEN(ip6hdr) + IP6_HLEN), p->tot_len));
        }
        /* free (drop) packet pbufs */
        pbuf_free(p);
        IP6_STATS_INC(ip6.lenerr);
        IP6_STATS_INC(ip6.drop);
        return ERR_OK;
    }

    /* Trim pbuf. This should have been done at the netif layer,
     * but we'll do it anyway just to be sure that its done. */
    pbuf_realloc(p, IP6_HLEN + IP6H_PLEN(ip6hdr));

    /* copy IP addresses to aligned ip6_addr_t */
    ip_addr_copy_from_ip6(ip_data.current_iphdr_dest, ip6hdr->dest);
    ip_addr_copy_from_ip6(ip_data.current_iphdr_src, ip6hdr->src);

    /* Don't accept virtual IPv4 mapped IPv6 addresses.
     * Don't accept multicast source addresses. */
    if (ip6_addr_isipv4mappedipv6(ip_2_ip6(&ip_data.current_iphdr_dest)) ||
            ip6_addr_isipv4mappedipv6(ip_2_ip6(&ip_data.current_iphdr_src)) ||
            ip6_addr_ismulticast(ip_2_ip6(&ip_data.current_iphdr_src)))
    {
        IP6_STATS_INC(ip6.err);
        IP6_STATS_INC(ip6.drop);
        return ERR_OK;
    }

    /* current header pointer. */
    ip_data.current_ip6_header = ip6hdr;

    /* In netif, used in case we need to send ICMPv6 packets back. */
    ip_data.current_netif = inp;
    ip_data.current_input_netif = inp;

    /* match packet against an interface, i.e. is this packet for us? */
    if (ip6_addr_ismulticast(ip6_current_dest_addr()))
    {
        /* Always joined to multicast if-local and link-local all-nodes group. */
        if (ip6_addr_isallnodes_iflocal(ip6_current_dest_addr()) ||
                ip6_addr_isallnodes_linklocal(ip6_current_dest_addr()))
        {
            netif = inp;
        }
#if LWIP_IPV6_MLD
        else if (mld6_lookfor_group(inp, ip6_current_dest_addr()))
        {
            netif = inp;
        }
#else /* LWIP_IPV6_MLD */
        else if (ip6_addr_issolicitednode(ip6_current_dest_addr()))
        {
            /* Filter solicited node packets when MLD is not enabled
             * (for Neighbor discovery). */
            netif = NULL;
            for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++)
            {
                if (ip6_addr_isvalid(netif_ip6_addr_state(inp, i)) &&
                        ip6_addr_cmp_solicitednode(ip6_current_dest_addr(), netif_ip6_addr(inp, i)))
                {
                    netif = inp;
                    LWIP_DEBUGF(IP6_DEBUG, ("ip6_input: solicited node packet accepted on interface %c%c\n",
                                            netif->name[0], netif->name[1]));
                    break;
                }
            }
        }
#endif /* LWIP_IPV6_MLD */
        else
        {
            netif = NULL;
        }
    }
    else
    {
        /* start trying with inp. if that's not acceptable, start walking the
           list of configured netifs.
           'first' is used as a boolean to mark whether we started walking the list */
        int first = 1;
        netif = inp;
        do
        {
            /* interface is up? */
            if (netif_is_up(netif))
            {
                /* unicast to this interface address? address configured? */
                for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++)
                {
                    if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
                            ip6_addr_cmp(ip6_current_dest_addr(), netif_ip6_addr(netif, i)))
                    {
                        /* exit outer loop */
                        goto netif_found;
                    }
                }
            }
            if (first)
            {
                if (ip6_addr_islinklocal(ip6_current_dest_addr())
#if !LWIP_NETIF_LOOPBACK || LWIP_HAVE_LOOPIF
                        || ip6_addr_isloopback(ip6_current_dest_addr())
#endif /* !LWIP_NETIF_LOOPBACK || LWIP_HAVE_LOOPIF */
                   )
                {
                    /* Do not match link-local addresses to other netifs. The loopback
                     * address is to be considered link-local and packets to it should be
                     * dropped on other interfaces, as per RFC 4291 Sec. 2.5.3. This
                     * requirement cannot be implemented in the case that loopback
                     * traffic is sent across a non-loopback interface, however.
                     */
                    netif = NULL;
                    break;
                }
                first = 0;
                netif = netif_list;
            }
            else
            {
                netif = netif->next;
            }
            if (netif == inp)
            {
                netif = netif->next;
            }
        }
        while (netif != NULL);
netif_found:
        LWIP_DEBUGF(IP6_DEBUG, ("ip6_input: packet accepted on interface %c%c\n",
                                netif ? netif->name[0] : 'X', netif ? netif->name[1] : 'X'));
    }

    /* "::" packet source address? (used in duplicate address detection) */
    if (ip6_addr_isany(ip6_current_src_addr()) &&
            (!ip6_addr_issolicitednode(ip6_current_dest_addr())))
    {
        /* packet source is not valid */
        /* free (drop) packet pbufs */
        LWIP_DEBUGF(IP6_DEBUG, ("ip6_input: packet with src ANY_ADDRESS dropped\n"));
        pbuf_free(p);
        IP6_STATS_INC(ip6.drop);
        goto ip6_input_cleanup;
    }

    /* packet not for us? */
    if (netif == NULL)
    {
        /* packet not for us, route or discard */
        LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_TRACE, ("ip6_input: packet not for us.\n"));
#if LWIP_IPV6_FORWARD
        /* non-multicast packet? */
        if (!ip6_addr_ismulticast(ip6_current_dest_addr()))
        {
            /* try to forward IP packet on (other) interfaces */
            ip6_forward(p, ip6hdr, inp);
        }
#endif /* LWIP_IPV6_FORWARD */
        pbuf_free(p);
        goto ip6_input_cleanup;
    }

    /* current netif pointer. */
    ip_data.current_netif = netif;

    /* Save next header type. */
    nexth = IP6H_NEXTH(ip6hdr);

    /* Init header length. */
    hlen = ip_data.current_ip_header_tot_len = IP6_HLEN;

    /* Move to payload. */
    pbuf_header(p, -IP6_HLEN);

    /* Process known option extension headers, if present. */
    while (nexth != IP6_NEXTH_NONE)
    {
        switch (nexth)
        {
        case IP6_NEXTH_HOPBYHOP:
            LWIP_DEBUGF(IP6_DEBUG, ("ip6_input: packet with Hop-by-Hop options header\n"));
            /* Get next header type. */
            nexth = *((u8_t *)p->payload);

            /* Get the header length. */
            hlen = 8 * (1 + * ((u8_t *)p->payload + 1));
            ip_data.current_ip_header_tot_len += hlen;

            /* Skip over this header. */
            if (hlen > p->len)
            {
                LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
                            ("IPv6 options header (hlen %"U16_F") does not fit in first pbuf (len %"U16_F"), IPv6 packet dropped.\n",
                             hlen, p->len));
                /* free (drop) packet pbufs */
                pbuf_free(p);
                IP6_STATS_INC(ip6.lenerr);
                IP6_STATS_INC(ip6.drop);
                goto ip6_input_cleanup;
            }

            pbuf_header(p, -(s16_t)hlen);
            break;
        case IP6_NEXTH_DESTOPTS:
            LWIP_DEBUGF(IP6_DEBUG, ("ip6_input: packet with Destination options header\n"));
            /* Get next header type. */
            nexth = *((u8_t *)p->payload);

            /* Get the header length. */
            hlen = 8 * (1 + * ((u8_t *)p->payload + 1));
            ip_data.current_ip_header_tot_len += hlen;

            /* Skip over this header. */
            if (hlen > p->len)
            {
                LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
                            ("IPv6 options header (hlen %"U16_F") does not fit in first pbuf (len %"U16_F"), IPv6 packet dropped.\n",
                             hlen, p->len));
                /* free (drop) packet pbufs */
                pbuf_free(p);
                IP6_STATS_INC(ip6.lenerr);
                IP6_STATS_INC(ip6.drop);
                goto ip6_input_cleanup;
            }

            pbuf_header(p, -(s16_t)hlen);
            break;
        case IP6_NEXTH_ROUTING:
            LWIP_DEBUGF(IP6_DEBUG, ("ip6_input: packet with Routing header\n"));
            /* Get next header type. */
            nexth = *((u8_t *)p->payload);

            /* Get the header length. */
            hlen = 8 * (1 + * ((u8_t *)p->payload + 1));
            ip_data.current_ip_header_tot_len += hlen;

            /* Skip over this header. */
            if (hlen > p->len)
            {
                LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
                            ("IPv6 options header (hlen %"U16_F") does not fit in first pbuf (len %"U16_F"), IPv6 packet dropped.\n",
                             hlen, p->len));
                /* free (drop) packet pbufs */
                pbuf_free(p);
                IP6_STATS_INC(ip6.lenerr);
                IP6_STATS_INC(ip6.drop);
                goto ip6_input_cleanup;
            }

            pbuf_header(p, -(s16_t)hlen);
            break;

        case IP6_NEXTH_FRAGMENT:
        {
            struct ip6_frag_hdr *frag_hdr;
            LWIP_DEBUGF(IP6_DEBUG, ("ip6_input: packet with Fragment header\n"));

            frag_hdr = (struct ip6_frag_hdr *)p->payload;

            /* Get next header type. */
            nexth = frag_hdr->_nexth;

            /* Fragment Header length. */
            hlen = 8;
            ip_data.current_ip_header_tot_len += hlen;

            /* Make sure this header fits in current pbuf. */
            if (hlen > p->len)
            {
                LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
                            ("IPv6 options header (hlen %"U16_F") does not fit in first pbuf (len %"U16_F"), IPv6 packet dropped.\n",
                             hlen, p->len));
                /* free (drop) packet pbufs */
                pbuf_free(p);
                IP6_FRAG_STATS_INC(ip6_frag.lenerr);
                IP6_FRAG_STATS_INC(ip6_frag.drop);
                goto ip6_input_cleanup;
            }

            /* Offset == 0 and more_fragments == 0? */
            if ((frag_hdr->_fragment_offset &
                    PP_HTONS(IP6_FRAG_OFFSET_MASK | IP6_FRAG_MORE_FLAG)) == 0)
            {
                /* This is a 1-fragment packet, usually a packet that we have
                 * already reassembled. Skip this header anc continue. */
                pbuf_header(p, -(s16_t)hlen);
            }
            else
            {
#if LWIP_IPV6_REASS

                /* reassemble the packet */
                p = ip6_reass(p);
                /* packet not fully reassembled yet? */
                if (p == NULL)
                {
                    goto ip6_input_cleanup;
                }

                /* Returned p point to IPv6 header.
                 * Update all our variables and pointers and continue. */
                ip6hdr = (struct ip6_hdr *)p->payload;
                nexth = IP6H_NEXTH(ip6hdr);
                hlen = ip_data.current_ip_header_tot_len = IP6_HLEN;
                pbuf_header(p, -IP6_HLEN);

#else /* LWIP_IPV6_REASS */
                /* free (drop) packet pbufs */
                LWIP_DEBUGF(IP6_DEBUG, ("ip6_input: packet with Fragment header dropped (with LWIP_IPV6_REASS==0)\n"));
                pbuf_free(p);
                IP6_STATS_INC(ip6.opterr);
                IP6_STATS_INC(ip6.drop);
                goto ip6_input_cleanup;
#endif /* LWIP_IPV6_REASS */
            }
            break;
        }
        default:
            goto options_done;
            break;
        }
    }
options_done:

    /* p points to IPv6 header again. */
    pbuf_header_force(p, (s16_t)ip_data.current_ip_header_tot_len);

    /* send to upper layers */
    LWIP_DEBUGF(IP6_DEBUG, ("ip6_input: \n"));
    ip6_debug_print(p);
    LWIP_DEBUGF(IP6_DEBUG, ("ip6_input: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len));

#if LWIP_RAW
    /* raw input did not eat the packet? */
    if (raw_input(p, inp) == 0)
#endif /* LWIP_RAW */
    {
        switch (nexth)
        {
        case IP6_NEXTH_NONE:
            pbuf_free(p);
            break;
#if LWIP_UDP
        case IP6_NEXTH_UDP:
#if LWIP_UDPLITE
        case IP6_NEXTH_UDPLITE:
#endif /* LWIP_UDPLITE */
            /* Point to payload. */
            pbuf_header(p, -(s16_t)ip_data.current_ip_header_tot_len);
            udp_input(p, inp);
            break;
#endif /* LWIP_UDP */
#if LWIP_TCP
        case IP6_NEXTH_TCP:
            /* Point to payload. */
            pbuf_header(p, -(s16_t)ip_data.current_ip_header_tot_len);
            tcp_input(p, inp);
            break;
#endif /* LWIP_TCP */
#if LWIP_ICMP6
        case IP6_NEXTH_ICMP6:
            /* Point to payload. */
            pbuf_header(p, -(s16_t)ip_data.current_ip_header_tot_len);
            icmp6_input(p, inp);
            break;
#endif /* LWIP_ICMP */
        default:
#if LWIP_ICMP6
            /* send ICMP parameter problem unless it was a multicast or ICMPv6 */
            if ((!ip6_addr_ismulticast(ip6_current_dest_addr())) &&
                    (IP6H_NEXTH(ip6hdr) != IP6_NEXTH_ICMP6))
            {
                icmp6_param_problem(p, ICMP6_PP_HEADER, ip_data.current_ip_header_tot_len - hlen);
            }
#endif /* LWIP_ICMP */
            LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip6_input: Unsupported transport protocol %"U16_F"\n", (u16_t)IP6H_NEXTH(ip6hdr)));
            pbuf_free(p);
            IP6_STATS_INC(ip6.proterr);
            IP6_STATS_INC(ip6.drop);
            break;
        }
    }

ip6_input_cleanup:
    ip_data.current_netif = NULL;
    ip_data.current_input_netif = NULL;
    ip_data.current_ip6_header = NULL;
    ip_data.current_ip_header_tot_len = 0;
    ip6_addr_set_zero(ip6_current_src_addr());
    ip6_addr_set_zero(ip6_current_dest_addr());

    return ERR_OK;
}


/**
 * Sends an IPv6 packet on a network interface. This function constructs
 * the IPv6 header. If the source IPv6 address is NULL, the IPv6 "ANY" address is
 * used as source (usually during network startup). If the source IPv6 address it
 * IP6_ADDR_ANY, the most appropriate IPv6 address of the outgoing network
 * interface is filled in as source address. If the destination IPv6 address is
 * LWIP_IP_HDRINCL, p is assumed to already include an IPv6 header and
 * p->payload points to it instead of the data.
 *
 * @param p the packet to send (p->payload points to the data, e.g. next
            protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
            IPv6 header and p->payload points to that IPv6 header)
 * @param src the source IPv6 address to send from (if src == IP6_ADDR_ANY, an
 *         IP address of the netif is selected and used as source address.
 *         if src == NULL, IP6_ADDR_ANY is used as source)
 * @param dest the destination IPv6 address to send the packet to
 * @param hl the Hop Limit value to be set in the IPv6 header
 * @param tc the Traffic Class value to be set in the IPv6 header
 * @param nexth the Next Header to be set in the IPv6 header
 * @param netif the netif on which to send this packet
 * @return ERR_OK if the packet was sent OK
 *         ERR_BUF if p doesn't have enough space for IPv6/LINK headers
 *         returns errors returned by netif->output
 */
err_t
ip6_output_if(struct pbuf *p, const ip6_addr_t *src, const ip6_addr_t *dest,
              u8_t hl, u8_t tc,
              u8_t nexth, struct netif *netif)
{
    const ip6_addr_t *src_used = src;
    if (dest != LWIP_IP_HDRINCL)
    {
        if (src != NULL && ip6_addr_isany(src))
        {
            src_used = ip_2_ip6(ip6_select_source_address(netif, dest));
            if ((src_used == NULL) || ip6_addr_isany(src_used))
            {
                /* No appropriate source address was found for this packet. */
                LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip6_output: No suitable source address for packet.\n"));
                IP6_STATS_INC(ip6.rterr);
                return ERR_RTE;
            }
        }
    }
    return ip6_output_if_src(p, src_used, dest, hl, tc, nexth, netif);
}

/**
 * Same as ip6_output_if() but 'src' address is not replaced by netif address
 * when it is 'any'.
 */
err_t
ip6_output_if_src(struct pbuf *p, const ip6_addr_t *src, const ip6_addr_t *dest,
                  u8_t hl, u8_t tc,
                  u8_t nexth, struct netif *netif)
{
    struct ip6_hdr *ip6hdr;
    ip6_addr_t dest_addr;

    LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);

    /* Should the IPv6 header be generated or is it already included in p? */
    if (dest != LWIP_IP_HDRINCL)
    {
        /* generate IPv6 header */
        if (pbuf_header(p, IP6_HLEN))
        {
            LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip6_output: not enough room for IPv6 header in pbuf\n"));
            IP6_STATS_INC(ip6.err);
            return ERR_BUF;
        }

        ip6hdr = (struct ip6_hdr *)p->payload;
        LWIP_ASSERT("check that first pbuf can hold struct ip6_hdr",
                    (p->len >= sizeof(struct ip6_hdr)));

        IP6H_HOPLIM_SET(ip6hdr, hl);
        IP6H_NEXTH_SET(ip6hdr, nexth);

        /* dest cannot be NULL here */
        ip6_addr_copy(ip6hdr->dest, *dest);

        IP6H_VTCFL_SET(ip6hdr, 6, tc, 0);
        IP6H_PLEN_SET(ip6hdr, p->tot_len - IP6_HLEN);

        if (src == NULL)
        {
            src = IP6_ADDR_ANY6;
        }
        /* src cannot be NULL here */
        ip6_addr_copy(ip6hdr->src, *src);

    }
    else
    {
        /* IP header already included in p */
        ip6hdr = (struct ip6_hdr *)p->payload;
        ip6_addr_copy(dest_addr, ip6hdr->dest);
        dest = &dest_addr;
    }

    IP6_STATS_INC(ip6.xmit);

    LWIP_DEBUGF(IP6_DEBUG, ("ip6_output_if: %c%c%"U16_F"\n", netif->name[0], netif->name[1], (u16_t)netif->num));
    ip6_debug_print(p);

#if ENABLE_LOOPBACK
    {
        int i;
#if !LWIP_HAVE_LOOPIF
        if (ip6_addr_isloopback(dest))
        {
            return netif_loop_output(netif, p);
        }
#endif /* !LWIP_HAVE_LOOPIF */
        for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++)
        {
            if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
                    ip6_addr_cmp(dest, netif_ip6_addr(netif, i)))
            {
                /* Packet to self, enqueue it for loopback */
                LWIP_DEBUGF(IP6_DEBUG, ("netif_loop_output()\n"));
                return netif_loop_output(netif, p);
            }
        }
    }
#endif /* ENABLE_LOOPBACK */
#if LWIP_IPV6_FRAG
    /* don't fragment if interface has mtu set to 0 [loopif] */
    if (netif->mtu && (p->tot_len > nd6_get_destination_mtu(dest, netif)))
    {
        return ip6_frag(p, netif, dest);
    }
#endif /* LWIP_IPV6_FRAG */

    LWIP_DEBUGF(IP6_DEBUG, ("netif->output_ip6()\n"));
    return netif->output_ip6(netif, p, dest);
}

/**
 * Simple interface to ip6_output_if. It finds the outgoing network
 * interface and calls upon ip6_output_if to do the actual work.
 *
 * @param p the packet to send (p->payload points to the data, e.g. next
            protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
            IPv6 header and p->payload points to that IPv6 header)
 * @param src the source IPv6 address to send from (if src == IP6_ADDR_ANY, an
 *         IP address of the netif is selected and used as source address.
 *         if src == NULL, IP6_ADDR_ANY is used as source)
 * @param dest the destination IPv6 address to send the packet to
 * @param hl the Hop Limit value to be set in the IPv6 header
 * @param tc the Traffic Class value to be set in the IPv6 header
 * @param nexth the Next Header to be set in the IPv6 header
 *
 * @return ERR_RTE if no route is found
 *         see ip_output_if() for more return values
 */
err_t
ip6_output(struct pbuf *p, const ip6_addr_t *src, const ip6_addr_t *dest,
           u8_t hl, u8_t tc, u8_t nexth)
{
    struct netif *netif;
    struct ip6_hdr *ip6hdr;
    ip6_addr_t src_addr, dest_addr;

    LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);

    if (dest != LWIP_IP_HDRINCL)
    {
        netif = ip6_route(src, dest);
    }
    else
    {
        /* IP header included in p, read addresses. */
        ip6hdr = (struct ip6_hdr *)p->payload;
        ip6_addr_copy(src_addr, ip6hdr->src);
        ip6_addr_copy(dest_addr, ip6hdr->dest);
        netif = ip6_route(&src_addr, &dest_addr);
    }

    if (netif == NULL)
    {
        LWIP_DEBUGF(IP6_DEBUG, ("ip6_output: no route for %"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F"\n",
                                IP6_ADDR_BLOCK1(dest),
                                IP6_ADDR_BLOCK2(dest),
                                IP6_ADDR_BLOCK3(dest),
                                IP6_ADDR_BLOCK4(dest),
                                IP6_ADDR_BLOCK5(dest),
                                IP6_ADDR_BLOCK6(dest),
                                IP6_ADDR_BLOCK7(dest),
                                IP6_ADDR_BLOCK8(dest)));
        IP6_STATS_INC(ip6.rterr);
        return ERR_RTE;
    }

    return ip6_output_if(p, src, dest, hl, tc, nexth, netif);
}


#if LWIP_NETIF_HWADDRHINT
/** Like ip6_output, but takes and addr_hint pointer that is passed on to netif->addr_hint
 *  before calling ip6_output_if.
 *
 * @param p the packet to send (p->payload points to the data, e.g. next
            protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
            IPv6 header and p->payload points to that IPv6 header)
 * @param src the source IPv6 address to send from (if src == IP6_ADDR_ANY, an
 *         IP address of the netif is selected and used as source address.
 *         if src == NULL, IP6_ADDR_ANY is used as source)
 * @param dest the destination IPv6 address to send the packet to
 * @param hl the Hop Limit value to be set in the IPv6 header
 * @param tc the Traffic Class value to be set in the IPv6 header
 * @param nexth the Next Header to be set in the IPv6 header
 * @param addr_hint address hint pointer set to netif->addr_hint before
 *        calling ip_output_if()
 *
 * @return ERR_RTE if no route is found
 *         see ip_output_if() for more return values
 */
err_t
ip6_output_hinted(struct pbuf *p, const ip6_addr_t *src, const ip6_addr_t *dest,
                  u8_t hl, u8_t tc, u8_t nexth, u8_t *addr_hint)
{
    struct netif *netif;
    struct ip6_hdr *ip6hdr;
    ip6_addr_t src_addr, dest_addr;
    err_t err;

    LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);

    if (dest != LWIP_IP_HDRINCL)
    {
        netif = ip6_route(src, dest);
    }
    else
    {
        /* IP header included in p, read addresses. */
        ip6hdr = (struct ip6_hdr *)p->payload;
        ip6_addr_copy(src_addr, ip6hdr->src);
        ip6_addr_copy(dest_addr, ip6hdr->dest);
        netif = ip6_route(&src_addr, &dest_addr);
    }

    if (netif == NULL)
    {
        LWIP_DEBUGF(IP6_DEBUG, ("ip6_output: no route for %"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F"\n",
                                IP6_ADDR_BLOCK1(dest),
                                IP6_ADDR_BLOCK2(dest),
                                IP6_ADDR_BLOCK3(dest),
                                IP6_ADDR_BLOCK4(dest),
                                IP6_ADDR_BLOCK5(dest),
                                IP6_ADDR_BLOCK6(dest),
                                IP6_ADDR_BLOCK7(dest),
                                IP6_ADDR_BLOCK8(dest)));
        IP6_STATS_INC(ip6.rterr);
        return ERR_RTE;
    }

    NETIF_SET_HWADDRHINT(netif, addr_hint);
    err = ip6_output_if(p, src, dest, hl, tc, nexth, netif);
    NETIF_SET_HWADDRHINT(netif, NULL);

    return err;
}
#endif /* LWIP_NETIF_HWADDRHINT*/

#if LWIP_IPV6_MLD
/**
 * Add a hop-by-hop options header with a router alert option and padding.
 *
 * Used by MLD when sending a Multicast listener report/done message.
 *
 * @param p the packet to which we will prepend the options header
 * @param nexth the next header protocol number (e.g. IP6_NEXTH_ICMP6)
 * @param value the value of the router alert option data (e.g. IP6_ROUTER_ALERT_VALUE_MLD)
 * @return ERR_OK if hop-by-hop header was added, ERR_* otherwise
 */
err_t
ip6_options_add_hbh_ra(struct pbuf *p, u8_t nexth, u8_t value)
{
    struct ip6_hbh_hdr *hbh_hdr;

    /* Move pointer to make room for hop-by-hop options header. */
    if (pbuf_header(p, sizeof(struct ip6_hbh_hdr)))
    {
        LWIP_DEBUGF(IP6_DEBUG, ("ip6_options: no space for options header\n"));
        IP6_STATS_INC(ip6.err);
        return ERR_BUF;
    }

    hbh_hdr = (struct ip6_hbh_hdr *)p->payload;

    /* Set fields. */
    hbh_hdr->_nexth = nexth;
    hbh_hdr->_hlen = 0;
    hbh_hdr->_ra_opt_type = IP6_ROUTER_ALERT_OPTION;
    hbh_hdr->_ra_opt_dlen = 2;
    hbh_hdr->_ra_opt_data = value;
    hbh_hdr->_padn_opt_type = IP6_PADN_ALERT_OPTION;
    hbh_hdr->_padn_opt_dlen = 0;

    return ERR_OK;
}
#endif /* LWIP_IPV6_MLD */

#if IP6_DEBUG
/* Print an IPv6 header by using LWIP_DEBUGF
 * @param p an IPv6 packet, p->payload pointing to the IPv6 header
 */
void
ip6_debug_print(struct pbuf *p)
{
    struct ip6_hdr *ip6hdr = (struct ip6_hdr *)p->payload;

    LWIP_DEBUGF(IP6_DEBUG, ("IPv6 header:\n"));
    LWIP_DEBUGF(IP6_DEBUG, ("+-------------------------------+\n"));
    LWIP_DEBUGF(IP6_DEBUG, ("| %2"U16_F" |  %3"U16_F"  |      %7"U32_F"     | (ver, class, flow)\n",
                            IP6H_V(ip6hdr),
                            IP6H_TC(ip6hdr),
                            IP6H_FL(ip6hdr)));
    LWIP_DEBUGF(IP6_DEBUG, ("+-------------------------------+\n"));
    LWIP_DEBUGF(IP6_DEBUG, ("|     %5"U16_F"     |  %3"U16_F"  |  %3"U16_F"  | (plen, nexth, hopl)\n",
                            IP6H_PLEN(ip6hdr),
                            IP6H_NEXTH(ip6hdr),
                            IP6H_HOPLIM(ip6hdr)));
    LWIP_DEBUGF(IP6_DEBUG, ("+-------------------------------+\n"));
    LWIP_DEBUGF(IP6_DEBUG, ("|  %4"X32_F" |  %4"X32_F" |  %4"X32_F" |  %4"X32_F" | (src)\n",
                            IP6_ADDR_BLOCK1(&(ip6hdr->src)),
                            IP6_ADDR_BLOCK2(&(ip6hdr->src)),
                            IP6_ADDR_BLOCK3(&(ip6hdr->src)),
                            IP6_ADDR_BLOCK4(&(ip6hdr->src))));
    LWIP_DEBUGF(IP6_DEBUG, ("|  %4"X32_F" |  %4"X32_F" |  %4"X32_F" |  %4"X32_F" |\n",
                            IP6_ADDR_BLOCK5(&(ip6hdr->src)),
                            IP6_ADDR_BLOCK6(&(ip6hdr->src)),
                            IP6_ADDR_BLOCK7(&(ip6hdr->src)),
                            IP6_ADDR_BLOCK8(&(ip6hdr->src))));
    LWIP_DEBUGF(IP6_DEBUG, ("+-------------------------------+\n"));
    LWIP_DEBUGF(IP6_DEBUG, ("|  %4"X32_F" |  %4"X32_F" |  %4"X32_F" |  %4"X32_F" | (dest)\n",
                            IP6_ADDR_BLOCK1(&(ip6hdr->dest)),
                            IP6_ADDR_BLOCK2(&(ip6hdr->dest)),
                            IP6_ADDR_BLOCK3(&(ip6hdr->dest)),
                            IP6_ADDR_BLOCK4(&(ip6hdr->dest))));
    LWIP_DEBUGF(IP6_DEBUG, ("|  %4"X32_F" |  %4"X32_F" |  %4"X32_F" |  %4"X32_F" |\n",
                            IP6_ADDR_BLOCK5(&(ip6hdr->dest)),
                            IP6_ADDR_BLOCK6(&(ip6hdr->dest)),
                            IP6_ADDR_BLOCK7(&(ip6hdr->dest)),
                            IP6_ADDR_BLOCK8(&(ip6hdr->dest))));
    LWIP_DEBUGF(IP6_DEBUG, ("+-------------------------------+\n"));
}
#endif /* IP6_DEBUG */

#endif /* LWIP_IPV6 */
